Floating roof tank seal



Oct. 23, 1962 w, JQQR, 3,059,806

FLOATING ROOF TANK SEAL Filed Oct. 12. 1959 3 Sheets-Sheet 1 Q III!!!" IINVENTOR. Vv/ll/am 5. door, E

ATTORNEY i Oct. 23, 1962 w. E. JOQR, n

FLOATING ROOF TANK SEAL 3 Sheets-Sheet 2 Filed Oct. 12. 1959 INVENTOR.VV////am 5. door ,1?

Oct. 23, 1962 w. E. JOOR, n

' FLOATING ROOF TANK SEAL 3 Sheets-Sheet 3 Filed 001;. 12, 1959INVENTOR. W////a m 4/00/51? ATTDR/VEV United rates Patent @hfiee3,059,806 Patented Oct. 23, 196.2

3,059,806 FLOATING ROOF TANK SEAL William E. Joor II, R0. Box 3052,Houston 1, Tex. Filed Oct. 12, 1959, Ser. No. 846,011 2 Claims. (Cl.220-26) This invention relates to floating roof tanks and particularlyto roof seals therefor.

It is necessary in such tanks to provide suflicient clear ance betweenthe roof and the tank Wall to permit free, vertical reciprocation of theroof within the tank. Such clearance is also necessitated by the factthat large tanks cannot be built accurately cylindrical. For instance,the tank wall, in horizontal section, may be slightly elliptical, or mayhave one or more nodes around the periphery thereof. Suchout-of-roundness may be due to locked up stresses set up during fieldwelding of the tank wall or to inaccuracies in the plate contours beforeassembly, or both. Where volatile liquids are to be stored, thisclearance must be provided with an adequate seal which not only does notimpede normal roof movements, but which also will accommodate itself tovariations in the tank Wall contour both vertically andcircumferentially.

Accordingly, it is the main object of the present invention to providesuch a floating roof tank seal.

Another object is to provide a seal for floating roof tanks embodying anannular fluid-distending bag and means for supporting the bag in sealingposition, which means is located wholly outside the bag in position forready inspection and so as to avoid corrosion or gumming of the hangerarms or their pivotal attachments due to the weighting and distendingliquid in the bag and also contamination of the weighting liquid, as bycoatings or lubricants on the arms.

Still another object is to provide an annular, bag-type seal forfloating roof tanks in which the sealing bag is supported by outwardlyand upwardly inclined hanger arms bridged between the roof and tank andhaving antifriction means bearing against the tank wall.

These objects and other more detailed objects here after appearing areattained by my novel roof seal structure which comprises, generally, anannular, closed (doughnut shaped) bag of pliable, imperforate materialinterposed in the space between the edge of the roof and the tank wall.The bag is supported by a plurality of radial, upwardly-inclined hangerarms located above the bag and having anti-friction means at their freeends bearing against the tank wall. Chains or straps depending from thearms are secured to and support the bag. Projecting upwardly from thefree ends of the arms are brackets which support a rain shield overlyingand closing the clearance space between the edge of the roof and thetank wall.

In the accompanying drawings which illustrate the invention, FIG. 1 is aperspective view of a floating roof tank embodying my novel seal, partsbeing broken away to illustrate the underlying structure.

FIG. 2 is an enlarged, vertical, transverse section through the sealingstructure.

FIG. 3 is an enlarged view of a detail of FIG. 2.

FIG. 4 is a partial vertical, transverse section taken substantially onthe line 4-4 of FIG. 2.

FIG. 5 is a partial horizontal section and plan view taken on line 5-5of FIG. 2.

FIG. 6 is a vertical transverse section illustrating a modified form ofseal.

FIG. 7 is a similar view illustrating still another form of seal.

The tank comprises a cylindrical wall 10 open at the top and receivingtherein a roof 11 having a generally conical main body and a peripheralpontoon 12. Access stairways are illustrated at 13.

bars 35 extend, intermittently,

Interposed within the space between roof edge plate 14 and the tank walland extending entirely around the root is an annular, doughnut shapedbag 15 made of pliable, imperforate material such as synthetic rubbercoated fabric. As best shown in FIG. 2, this bag material is crimped oroverlapped at its inner side, as at 16, where it is sealingly secured tothe horizontal flange of an angle bar 17 welded to roof edge plate 14.As shown in FIG. 3, rubber strips 18 are interposed between the fold orbight 16 of the bag and angle 17 and channels 19 laid on top of thefold. The area around strips 18 is suitably sealed, as by a rubbercement material, and the whole assembly secured by bolts 26 and washers21. A quantity of liquid 22, such as kerosene or other non-freezingmaterial, partially fills bag 15 for weighting and distending the sameto cause the outer part or sheet 23 of the bag to bear sealingly againstthe inner face of the adjacent tank wall. Bag 15 may be formed of asingle sheet of material which is first draped around the tank wall,then lifted at its lower edge to form the bottom of the bag. Clampedpart 16 may be either a fold or bight of continuous material, or theoverlapped ends of separate sheets. A plurality of hanger arms 25project radially and upwardly from the roof edge sheet 14 at regularintervals therearound and each arm 25 (FIGS. 4 and 5) has lcross bars 26and 27 at its opposite extremities. Each lower cross bar 26 is in theform of a hollow tube which receives a shaft 28 which, in turn, isjournaled in a pair of angle brackets 29 projecting from the roof edgesheet above bag attaching flange 17. The upper cross bar 27 of each armis, similarly, of tubular construction and receives a shaft 30 which, ateach end, mounts a roller 31. The; rollers 31 bear against the innerface of the tank Wall and form anti-friction means between the hangerarms and the tank wall.

Depending from each upper hanger arm cross bar 27, at opposite sides ofarm 25 and secured thereto by collars 32a, are a pair of chains 32which, at their lower extremities, are secured by means of lugs 33 andbolts 34 to bars 35 secured to the upper extremity of bag 15. Pairs ofentirely around bag 15, the upper extremities of sheets 23 and 36forming bag 15 being clamped between the pairs of bars 35 by means ofbolts 37. Preferably, shafts 30 are disaligned vertically with respectto the center of gravity of bag 15, in other words, closer to the tankwall so that the force of gravity tends to cause the bag to followirregularities in the tank wall so as to bear sealingly thereagainst.

Projecting upwardly from each upper cross bar 27 is a pair of brackets38, secured to chain supporting collars 32a, having acutely angledflanges 39 to which are secured an upwardly-angled secondary sealingmember 40, bear-- ing at its upper extremity against the tank wall, anda downwardly-extending rain shield sheet 41 having strengtheningcorrugations 42. Rain shield 41 rests at its lower extremity upon thetop of pontoon 12 so as to overlie and protect the clearance spacebetween the roof edge plate 14 and the tank wall.

In operation, it is obvious that as the roof rises and falls with theincrease and decrease of product liquid 4-3 in the tank, liquid weightedand distended bag 15 is, likewise, carried upward by hanger arms 25causing outer sheet 23 of the bag to slide along the tank wall. Becauseof anti-friction rollers 31, hanger arms 25 move smoothly along the tankWall and bag 15, because of its pliable nature, can yield, as required,to conform with irregularities in the tank wall and thereby maintain agood seal. Preferably, the roof and seal are designed so that the lowerpart of bag 15 depends below the surface of the product liquid, thuspreventing the formation of a gas pocket above the body of productliquid.

FIG. 6 shows a modification in which annular closed bag 46, partiallyfilled with distending fluid 47, slidably engages both the roof edgesheet 48 and the inner face of the tank wall 49. Radially and upwardlyinclined support arms 50, disposed at regular intervals about the roof,are pivotally attached to the roof, as in the previous form, by means oflugs 51. Rollers 52 at the upper extremities of arms 50, formanti-friction bearings between the arms and the tank wall. The upperportion of the bag is clamped between pairs of circumferential bars 53and these are secured to and supported by straps 54- depending fromhanger arms 50. Other straps 55 are secured to pairs of circumferentialbars 56 between which are clamped the lower edges of the bag formingpliable sheets. As in the first form, bag 46 may be formed by a singlesheet with its meeting edges cemented or merely clamped between pairs ofbars 53 or 56, or of two separate sheets of material with their meetingedges overlapped, clamped and sealed between both sets of clamping bars.Straps 55, at their lower extremities, are pivotally secured to bellcranks 57 which are pivotally attached to the bottom of roof pontoon 58by means of lugs 59. Weights 6% at the inner ends of bell cranks 57maintain anti-friction rollers 61 at the outer ends of these bell cranksin engagement with the tank wall. Accordingly, in this form, sealing bag46 with its distending fluid, liquid or gaseous, is maintained properlypositioned by opposing pivoted arms 50 and 57.

In the third modification shown in FIG. 7, annular, closed sealing bag64, is supported from pivoted hanger arms 65 by means of chains 66.Clamping bars 67 at the top of bag 64 are positioned slightly inwardlyof the brackets 68 which attach the upper ends of the chains to thehanger arms so that the force of gravity tends to maintain sealing bag64 bearing firmly against the tank wall, irrespective of irregularitiestherein. A protector sheet 69 extends from clamping bars 67 to angularbracket 76 projecting from tank roof edge sheet 71. A second bag 72rests against the upper, inner surface of bag 64. Bag 72 has a fillingof weighty material, solid as sand, or liquid, which being alsoeccentrically as well as swingably supported, tends to additionally urgeouter bag 64- into sealing engagement with the tank wall. A rain shield73 overlies the clearance space between the roof and tank wall, as inthe previous forms.

The novel, annular-bag-type, floating roof tank seal has a number ofimportant advantages over previous practice. The exposed positioning ofthe hanger arms fa cilitates inspection and repair without the necessityof draining the tank, since all supporting parts are readily accessible.The seal and its supports have fewer more rugged parts than previousseals and may be more easily and less expensively installed in the fieldand are less subject to mechanical trouble, thus requiring reducedmaintenance. The hanger arms may be used to ground the roof through thetank wall. Since there is no vapor space above the product, the partsare less subject to corrosion. The seal works better and is less subjectto wear when used in riveted tanks. Finally, the seal insures theapplication of substantially equal sealing pressure all aroundirrespective of tank wall irregularities and the sealing pressureincreases in case of an abnormal load on the roof.

The invention may be modified in various respects as will occur to thoseskilled in the art and the exclusive use of all modifications as comewithin the scope of the appended claims is contemplated.

I claim:

1. In a floating roof tank, a flexible seal between the tank wall androof comprising a bag of pliable material having a free hanging, belliedbottom and side flaps joined at their upper extremities, reinforcing barmeans secured to said joined extremities, fluid distending material insaid bag, support arms projecting from said roof above said bag andbearing against said wall, and tension members pivotally secured to andextending downwardly and inwardly from the outer portions of said armsand secured to said bar means for suspending said bag while biasing thesame against said tank wall.

2. A floating roof tank seal comprising an annular closed tube ofimperforate material interposed in the space between the edge of theroof and the tank wall and surrounding the roof, fluid material in saidtube for distending the same against the roof and tank wall, rigid barmeans secured to the upper portion of said tube, a plurality of armspivotally secured to the edge of the roof and extending radiallyupwardly therefrom above said tube and bearing against the tank wall,suspension elements depending from said arms and secured to said barmeans for supporting said tube, and weighted means eccentrically andswingably supported by said bar means and bearing against the inner faceof said tube for urging the same outwardly.

References Cited in the file of this patent UNITED STATES PATENTS Re.22,169 Hammeren Sept. 1, 1942, 2,066,292 Kuehn Dec. 29, 1936 2,314,805Wiggins Mar. 23, 1943 2,471,404 BOberg Mar. 31, 1949 2,531,424 Goldsbyet al. Nov. 28, 1950 2,735,573 Fino Feb. 21, 1956 2,968,420 Harris et alI an. 17, 1961 FOREIGN PATENTS 540,391 Germany Dec. 15, 1931

